Testing camera projecting into a 3d scene. The concept is to unload heavy math caluclations from the renderer by reprojecting the final composite onto the 3d geometry, and then quickly rendering depth of field and motion blur. Arnold makes such work-arounds obsolete, but in mental ray and other raytracers, these cheats go a long way.
Derek Jenson Blog
My website serves to archive experiments, document projects, share techniques, and motivate further exploration & artistry in 3d space.